Premises and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Depreciation expense for premises and equipment	$ 1,316,000	$ 1,268,000	$ 4,002,000	$ 3,849,000
Write down of fixed assets held for sale	1,934,000		1,934,000
Fixed assets transferred to held for sale	716,000		716,000
Estimated market value of property held for sale	$ 1,218,000		$ 1,218,000